Category: Calculators
Mulch Calculator
Work out how much mulch a bed or border needs
Enter the length, width and depth of a bed to estimate the mulch volume needed, and optionally the number of bags.
Length, width and depth must all use the same unit; the volume is in that unit cubed. Bag count only appears once a bag volume above zero is entered, in that same cubic unit.
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What this tool does
The calculator multiplies length by width by depth to get the volume, then adds your waste percentage for spillage and settling. If you also enter the volume one bag holds, the calculator divides the volume needed by that bag size and rounds up to a whole bag.
How to use it
- Enter the length, width and depth of the bed in one consistent unit.
- Enter a waste percentage for spillage and settling.
- Optionally enter the volume one bag of mulch holds.
- Read the volume needed, and the bag count if you entered a bag size.
Privacy
This tool runs entirely in your browser. Your input is never uploaded, stored or shared — closing the tab removes it.
Frequently asked questions
- What depth of mulch should I use?
- 2 to 4 inches (about 5 to 10 cm) is typical for most garden beds; thinner layers break down and weed less effectively, while much deeper layers can smother roots.
- How do I convert bag size into the same unit as the volume?
- Check the bag label for its volume, such as '2 cubic feet' or '50 liters', and convert it to match the cubic unit your length, width and depth are in before entering it.
- How much extra should I allow for waste?
- 5 to 10% covers spillage and settling over time for a typical bed; irregular borders or a first-time uneven surface often warrant a higher figure.